This invention relates to a stable, cosmetically elegant hydrocortisone hydroalcoholic solution useful for the relief of itching and inflammation associated with minor skin irritation when applied as a non-aerosol spray. It is relatively non-flammable and exhibits no microscopic crystallization. The preparation is primarily designed for the treatment of poison ivy and contact dermatitis, although it would also be useful for the treatment of minor burns, cuts, scratches, sunburn and other similar minor skin irritants.
Hydrocortisone, which is a naturally occuring steroid, is a white powder that is very slightly soluble in water but soluble in alcohol and glycol solvents. Its solubility at 25.degree. C. in water, ethanol and propylene glycol is 0.28, 15.0 and 12.7 mg/ml, respectively. It is also known as cortisol.
Hydrocortisone has been marketed in the United States since 1952 as a prescription drug and is recognized as one of the most potent and effective agents for the treatment of many common dermatoses. It has been commonly used for many years in various topical prescription preparations as an antipruritic and anti-inflammatory agent in the 0.5-5.0 percent dosage range. In recent years it has been used topically in a dosage range of 0.1-0.25 percent. It has recently been recommended by the OTC Topical Analgestic Panel of the FDA as a safe and effective topical analgesic product when applied at 0.25-0.50 percent to affected areas of the skin 3 to 4 times daily.
Topical hydrocortisone compositions have traditionally been sold in the form of ointments, lotions and creams. In U.S. Pat. No. 3,456,052 an aerosol ointment form was disclosed. Hydroalcoholic lotion solutions are also known but are generally found to be unstable, particularly at low temperature, with small amounts of hydrocortisone crystallizing out. This problem is not a great concern in these preparations since a small degree of crystallization will usually not seriously affect the use of a lotion which is rubbed on the skin, although if the crystallization is severe enough it could irritate inflamed, sensitive skin. In a spray device this problem is serious since even microscopic crystals can block the outlet orifice of the container and render the device inoperable.
The spray is a particularly desirable form since it is convenient and presents no danger of contamination to the product. A spray would also provide a generally cooling effect on the inflamed skin and cause less irritation to sensitive skin than would be produced by the rubbing on of a lotion or the like. However, the aerosols containing fluorocarbon propellants are undesirable for environmental reasons and the hydrocarbon propellants are highly flammable.